[PERFECT FIT]: The G52 po-laris spare part replacement valve kit is exactly compatible with Zodiac Polaris 180, 280, 380, 480 PRO, 3900 Sport, Vac-Sweep 380, Vac-Sweep 280, 280TankTrax.se jame [EASY TO USE]: No assembly required. The G52 relief valve is ready to install, just connect the fittings and hoses firmly to work. And opens every 3 minutes for 30 seconds to remove the cleaner by changing its cleaning direction. This valve is also able to pull the unit out of tight spots if it gets stuck [WHEN TO REPLACE IT]: When the po-laris 280/380pool backseat valve cleaner gets stuck on an obstacle or edge, or even when the emergency valve is still open but the nozzle no longer sprays water, you should consider checking or replacing it, Covienapp G52 emergency valve solves this problem Note: The data are all measured manually, please allow 1-3cm error due to differences in light and display, there may be some color differences, please refer to the actual item received.